Call ASP.NET PageMethod/WebMethod with jQuery - returns whole page

Question

jQuery 1.3.2, ASP.NET 2.0. Making an AJAX call to a PageMethod (WebMethod) returns the full/whole page instead of just the response. A breakpoint on the page method shows it's never getting hit. I have the [WebMethod] attribute on my method, and it is public static, returns string and accepts no params. I even tried adding [ScriptService] at the top of my class to see if it helped, but it did not.

I have seen this post http://stackoverflow.com/questions/348689/jquery-ajax-with-asp-net-webmethod-returning-entire-page which had my same symptoms, but I am still having a problem. I read http://encosia.com/2008/05/29/using-jquery-to-directly-call-aspnet-ajax-page-methods/ and I feel like I'm following this to the T, but still no luck.

The jQuery call I'm making is:

jQuery.ajax({
    type: 'POST',
    contentType: 'application/json; charset=utf-8',
    data: '{}',
    dataType: 'json',
    url: 'MyPage.aspx/SomePageMethod',
    success: function(result){
        alert(result);
    }
});

The request/response headers, as per Firebug in FF3, are as follows

Response Headers
Server  ASP.NET Development Server/8.0.0.0
Date    Tue, 24 Feb 2009 18:58:27 GMT
X-AspNet-Version    2.0.50727
Cache-Control   private
Content-Type    text/html; charset=utf-8
Content-Length  108558
Connection  Close

Request Headers 
Host    localhost:2624
User-Agent  Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.6) Gecko/2009011913 Firefox/3.0.6
Accept  application/json, text/javascript, */*
Accept-Language en-us,en;q=0.5
Accept-Encoding gzip,deflate
Accept-Charset  ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive  300
Connection  keep-alive
Content-Type    application/json; charset=utf-8
X-Requested-With XMLHttpRequest
Referer http://localhost:2624/MyApp/MyPage.aspx
Content-Length  2
Cookie  ASP.NET_SessionId=g1idhx55b5awyi55fvorj055;

I've added a ScriptManager to my page just for kicks to see if it helped, but no luck there.

Any suggestions?

Answer 1

Do you know that Page Methods are working properly? If you use the the ScriptManager do they work?

It sounds like you might be missing a web.config entry. Specifically the HttpModules section.

Answer 2

Most ajax scenarios I've seen really should call a web service or separate script handler, not a page. That is extremely easy to do in .net 3-5, not so easy in 2-0. Even after you figure out (if) how not to load the whole page, here are reasons not to call a page method:

1) The page method might load less stuff than a full page load, but still far more than you need for a simple ajax call. 2) Lousy separation of responsibilities. The page is probably responsible for nicely laying stuff out, not the logic you are using in the ajax method.
3) Maybe you need some session state, but that should still be available.

I'm currently updating my knowledge on this subject ... I'll look for a good answer to this question in this thread, or I'll post one next week. Here is the direction I am headed

1) Send JSON from server to client, and use javascript to update your page. - a variety of frameworks make it easy to produce JSON from the web server.
2) JQuery makes ajax calls, json handling, and client formatting fun, instead of painful.

Answer 3

OMG thankyou i spent all afternoon trying to debug this and i was missing one line from my web.config:

enter code here
<system.web>
  <httpModules>
    <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
  </httpModules>
</system.web>

Answer 4

I encountered this problem again today for a different reason: I had misspelled "application" in

contentType: 'application/json'

And was getting a full-page response instead of a call to the WebMethod.